The Characteristic Properties of Acids & Bases (CIE IGCSE Chemistry: Co-ordinated Sciences (Double Award))

Sulfurous acid forms salts called sulfites and contain the ion SO₃^2-

When barium nitrate solution is added to aqueous sulfurous acid, a white precipitate, A, forms. Bromine water changes from brown to colourless when added to aqueous sulfurous acid. 

Bromine oxidises sulfurous acid. When this solution is tested with acidified barium nitrate a different white precipitate B is formed. 

[1]

Complete the following word equations.

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[1]

Write equations for the reaction of dilute sulfuric acid with each of the following.

This question is concerned with the following oxides.

   aluminium oxide
   carbon monoxide
   copper(II) oxide
   silicon(IV) oxide
   sodium oxide
   sulfur dioxide
   zinc oxide

Choose one oxide from the above list to match each of the following descriptions. An oxide may be used once, more than once or not at all.

This oxide does not react with acid or alkali.

This oxide reacts with water to give a strong alkali solution.

This oxide is used as a bleach.

Extended tier only

This oxide is amphoteric.

This oxide has a giant covalent structure.

This oxide is soluble in water and it is acidic.

Match the following pH values to the solutions given below

The solutions all have the same concentration.

Extended tier only

This question is concerned with the following oxides.

sulfur dioxide
carbon monoxide
lithium oxide
aluminium oxide
nitrogen dioxide
strontium oxide

Two of the oxides are responsible for acid rain.

Identify the two oxides and explain their presence in the atmosphere.

Lithium oxide is an ionic compound.

Four bottles were known to contain aqueous ammonia, dilute hydrochloric acid, sodium hydroxide solution and vinegar, which is dilute ethanoic acid. The bottles had lost their labels. The pH values of the four solutions were 1, 4, 10 and 13.

Complete the table.

When nitric acid is added to water the following reaction occurs.

HNO₃ + H₂O → NO₃^– + H₃O⁺

Give the name and the formula of the particle which is transferred from nitric acid to water.

name

formula

Extended tier only

This question is concerned with the following oxides.

Sulfuric acid is a strong acid. Hexanesulfonic acid is also a strong acid. It has similar properties to sulfuric acid.

The formula of the hexanesulfonate ion is C₆H₁₃SO₃^–.

The formula of the barium ion is Ba²⁺. What is the formula of barium hexanesulfonate?

Complete the following equations.

A student investigates the reaction of small pieces of zinc with dilute sulfuric acid at 20 °C. The zinc is in excess.
Sulfuric acid is a compound.

Define the term compound.

State the formula of the ion that is present in an aqueous solution of all acids.

A few drops of the indicator methyl orange are added to aqueous dilute sulfuric acid. State the colour change observed

from orange to ____________________

The formula of sulfuric acid is H₂SO₄.
Complete Table 1 to calculate the relative molecular mass of sulfuric acid.
                          
                                                       Table 1

Aqueous sodium hydroxide is a base.

Complete this sentence about the different types of bases.
Bases are metal hydroxides or metal _______________________

Describe the reaction of aqueous sodium hydroxide with:

Ammonia is a soluble base.
Draw a circle around the pH value of aqueous ammonia.

                            pH 1    pH 5    pH 7    pH 10

Magnesium, calcium and strontium are Group II elements.

Calcium reacts with cold water to form two products:

• a colourless gas, P, which ‘pops’ with a lighted splint
• a weakly alkaline solution, Q, which turns milky when carbon dioxide is bubbled through it.

Name gas P.

Identify the ion responsible for making solution Q alkaline.

Suggest the pH of solution Q.

Write a symbol equation for the reaction of calcium with cold water.

Aqueous sodium hydroxide, NaOH (aq), is a strong alkali that reacts with dilute sulfuric acid exothermically.
What type of reaction is this?

Ethylamine is a weak base and sodium hydroxide is a strong base.

[2]

Ethylamine reacts with acids to form salts.

CH₃CH₂NH₂ + HCl → CH₃CH₂NH₃Cl
               ethylammonium chloride

Extended tier only

Gases diffuse, which means that they move to occupy the total available volume.

Complete the following equations for reactions of these two acids.

Ethylamine, CH₃–CH₂–NH₂, is a base which has similar properties to ammonia.

In aqueous ethylamine, there is the following equilibrium.

CH₃–CH₂–NH₂ + H₂O CH₃–CH₂–NH₃⁺ + OH^–

Explain why water is behaving as an acid in this reaction.

Explain the chemistry of the following reaction:

When aqueous ethylamine is added to aqueous iron(III) chloride, a brown precipitate is formed.

a)

[1]

[2]

Sulphuric acid is a typical strong acid.

Change the equations given into a different format.

Extended tier only

Antimony oxide is a white powder which is insoluble in water. Describe how you would find out if it is a basic, an acidic or an amphoteric oxide.